The present invention relates to data storage, and more particularly, to migrating data from one volume to a new target volume by merging bitmaps to maintain consistency.
Using conventional data storage systems, there is no automated way to migrate data from one target volume to a new target volume on the same storage system while maintaining disaster recovery capability. There are instances during normal operation of the data storage system when a user would desire for a different target volume to be used for replication of data, such as a volume on a higher performing disk in the system for improved performance, for reconfiguration purposes, etc. Currently, in order to achieve this switchover between target volumes, the process is manually performed, which is time consuming, error prone, and could potentially result in data loss. This manual process may become even more difficult when using a copy services solution that provides managed consistency across multiple copy relationship pairings because, generally, the need to switch volumes will only affect a few of the pairings within that consistency group/session. In order to perform this manually, the user would first have to remove the copy pairings for those volumes which form the session and then terminate the relationships. Then, a new relationship is established between the original source volume and the new target volume, and all of the data must be copied over. In order to maintain the integrity of the consistency group/session, this would have to be done outside of the consistency group/session and then added in once the volumes reach full duplex. Of course, beside the concern for errors, the user's data is not being replicated consistently throughout this manual and error-prone process, which introduces the possibility of replication errors and loss of data.
Therefore, a storage solution which automates the migration of data from one volume to a new target volume while maintaining consistency would be beneficial.